Add GPU warmup function for ZeroGPU detection

- Create warmup() function decorated with @spaces.GPU(duration=10)
- Add @spaces.GPU(duration=120) back to initialize_model()
- Call warmup() on gradio_app.load() to ensure GPU detected at startup
- Remove @spaces.GPU from wrapper functions (they call GPU methods internally)

ZeroGPU requires at least one GPU function invoked during startup.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app.py

@@ -38,6 +38,7 @@ class FoundationPoseInference:
         self.tracked_objects = {}
         self.use_real_model = USE_REAL_MODEL
 
+    @spaces.GPU(duration=120)
     def initialize_model(self):
         """Initialize the FoundationPose model on GPU."""
         if self.initialized:
@@ -262,8 +263,16 @@ async def api_estimate(request: EstimateRequest):
         raise HTTPException(status_code=500, detail=str(e))
 
 
+# Warmup function to ensure ZeroGPU detects GPU usage
+@spaces.GPU(duration=10)
+def warmup():
+    """Warmup function to initialize GPU context for ZeroGPU."""
+    logger.info("Warming up GPU for ZeroGPU...")
+    pose_estimator.initialize_model()
+    return "✓ GPU initialized"
+
+
 # Gradio wrapper functions
-@spaces.GPU(duration=120)
 def gradio_initialize(object_id: str, reference_files: List, fx: float, fy: float, cx: float, cy: float):
     """Gradio wrapper for object initialization."""
     try:
@@ -307,7 +316,6 @@ def gradio_initialize(object_id: str, reference_files: List, fx: float, fy: floa
         return f"Error: {str(e)}"
 
 
-@spaces.GPU(duration=30)
 def gradio_estimate(object_id: str, query_image: np.ndarray, fx: float, fy: float, cx: float, cy: float):
     """Gradio wrapper for pose estimation."""
     try:
@@ -484,6 +492,9 @@ with gr.Blocks(title="FoundationPose Inference", theme=gr.themes.Soft()) as grad
     See the [API documentation](https://huggingface.co/spaces/gpue/foundationpose) for details.
     """)
 
+    # Warmup on load to ensure ZeroGPU detects GPU usage
+    gradio_app.load(warmup, outputs=None)
+
 
 # Mount Gradio to FastAPI
 app = gr.mount_gradio_app(app, gradio_app, path="/")